Electkic low and high-voltage fuses



BEST AVAILABLE cop F. H. TURNHAM ET AL ELECTRIC LOW AND HIGH-VOLTAGEFUSES Aug. 14, 1951 s Shets-Sheet 1 Original Filed Jan. 21, 1948 BESTAVAiLABLE COP 1951 TURNHAM ET AL Re. 23,400

ELECTRIC LOW AND HIGH VOLTAGE FUSES 3 Sheets-Sheet 2 Original Filed Jan.21, 1948 BEST AVAILABLE CO Aug. 14, 1951 F. H. TURNHAM ET AL 23,400

ELECTRIC LOW AND HIGH-VOLTAGE FUSES Original Filed Jan. 21. 1948 3Sheets-Sheet 5 Reissuecl Aug. 14, 1951 BEST 05,:

ELECTRIC LOW AND HIGH-VOLTAGE FUSES Fitzhugh Hobson Turnham and EdgarWilliam Garrison, Jr., Birmingham, Ala., assignors to USCO Power andEquipment Corp., Birmingham, Ala., a corporation of Alabama Original No.2,485,221, dated October 18, 1949, Se-

rial No. 3,618, January 21, 1948. Application for reissue May 2, 1950,Serial No. 159,632

15 Claims.

Matter enclosed in heavy brackets appears in the original patent butforms no part of this reissue specification; matter printed in italicsindicates the additions made by reissue.

[This invention relates to low and high voltage electric fuses. It hasfor its main objects to provide such a fuse that will be highlyeiiicient for its purpose, simple in structure, comparatively cheap tomanufacture, and very durable] [A further object is to provide a doublebreak ing fuse, latched at both ends, this being a novel idea in suchdevices. The use of two tubes that break at the center of the span,results in a, great advantage in the springing means for moving the twoshort tubes into the open position rather than lifting one long tubeequal in length to the two short tubes] [A further object is to providea. latch on the hinge ends of the double breaking fuse that is sodesigned that when the tube is swung to the closed position the impactof latching the fuse imposes no stress or strain on the fuse link. Afurther advantage of the invention is that the two tubes are latched onthe mechanism ends and a fuse link is drawn through the two tubes to thelatches. The fusion of any part of the link will automatically unlatchboth tubes and the springs in the mechanism will swing the tubes fromclosed to open position. When the tube is in motion a cam binds on aspring-pressured brake that stops the two part tube with a minimum ofshock or impact on the supporting insulators] [Other objects andadvantages will appear from the drawings and description] [By referringto the drawings part of this application, it will be observed that Fig.l is an elevational view of the double breaking horizontal fuse; Fig. 2is an elevation of the hinge mechanism assembly in closed position; Fig.3 is an enlarged detail view of the connecting portions of the twotubes; Fig. 4 is an elevation of the hinge mechanism assembly in openposition, tube broken away; Figs. 5 and 6 are elevations of the latchassembly in open and closed positions; Fig. 7 is an end view of thelatch assembly in closed position; Fig. 8 is a detail view showingbraking mechanism, with cover removed, in closed position; Fig. 9 is adetail view showing braking mechanism, with cover removed, in openposition; Figs. 10 and 11 are detail cross sectional views showin springarrangement with tube in closed position.]

[Similar reference numerals refer to similar parts throughout theseveral views] [Referring to the drawings in detail it will be seen thatthe device comprises a main metal base I supporting insulators 2carrying individual bases 3. The two fuse tubes 4 and 4 are latched inclosed position by latches being engaged to catch members 6. The fuselink I is stretched through both tubes 4 and 4' and attached in slots oflink ejectors 8 and there held securely to the tube supports 9 by thumbscrews Ill. Springs ll tend to stretch the fuse link through the twotubes, and upon rupture of the link the springs ll rotate the ejectors 8about pins l2 thus moving the pins 8 on an are around pins l2. The pins8' of the ejectors 8 fit in slots 5 and when the arcs of the pins 8' arecompleted the latches 5 are moved or pivoted about pins [3 to theunlatched position. Thus this latch arrangement exerts no stress uponthe fuse link 1 except pressure of the springs ll. After the tubes 4 and4' are unlatched the springs l4 swing them around pins l5 to the openposition. The main tube castings 9 have cam arms 9' that move in arcsabout pins 15; each brake housing I6 is moved up in an are about thepins 1'! by the cam arm 9 binding on the inner curved surface of thehousing I6. As the housing IE is pivoted about pin I! the spring I8 iscompressed. Adjusting bolt I9 is stationary with the base 3 and can beloosened or tightened on the spring cover 20 to give the requiredpressure on the spring l8 to provide an easy and shockless movement ofthe tubes 4 and 4. Non-metallic covers 2| are connected to the ends ofthe tubes, and are mitered to a semiweathered proof condition for theends of the tubes] [The open position of the mechanism as shown in Fig.4 shows the latch and link ejector at rest in the completed, unlatchedposition. Note that the fuse link I has been drawn from the fuse tube,upon the fusion of the link, by the link ejector 8, and the frayed endsof the link are resting in the basket 22 shown in broken lines. SpringIB is in compression because cam arm 9' has completed its arc and raisedthe brake housing I 6 about pin [1.]

. [When the fuse link is threaded through the fuse tube the link ejector8 is pulled down to the latched position. In this position any pressureapplied to the latch 5 by catch member 6 does not exert any strain onthe fuse link. As the link ejector 8 has to move in are about pin [2,any pressure trying to move pin 8 will exert resulting force directlyinto pin l2. Spring ll flipping link ejector 8 around pin l2 moves pin8' engaged in slot 5. The latch 5 pivots about pin is resulting in acounterclockwise movement at point of contact of latch 5 to catch member6, this being the unlatching motion] [When the main tube casting member9-15 in closed position cam arm 9' is engaged to curved surface of thefriction housing I 6 at all times, but the pressure of spring I8 isnegative and the friction is slight. The friction being applied at alltimes, increasing as the fuse tube swings to the open position, reducesthe shock of the sudden stopping of the fuse tube.]

.[The spring arrangement for swinging the fuse tube to the open positionhas the springs I4 in series, thus the pressure tending to move the tubecasting member about pin has the advantage of both springs applied. Thesprings are supported by a mandrel 23 (spacer) on pin Ii. The stationaryend of the spring assembly is held attached by a clamp bolt 24 to themechanism base 3, while the other end presses on the main tube castingmember 9.]

[The various parts of the fuse may be made of any material suitable forthe purpose, but we prefer to use such metals and other materialsgenerally used in the manufacture of such electrical equipment. Also thedevice may be made in various sizes" and capacities. The inventionresides in the arrangement and combination of the parts, not thematerials of which they are made] [While we have shown and described thepreferred embodiment of our invention, we do not wish to limit same tothe exact and precise details of structure, but reserve the right tomake all modifications and changes so long as they remain Within thespirit and scope of the following claims] This invention relates to lowand high voltage electric fuses and has for its general object andpurpose to provide a durably constructed fuse of this type which will behighly efiicicnt in practical operation and embodies a comparativelysimple assembly of a minimum number of structural elements, wherebymaximum production economies may be realized.

A primary particular oby'ect of the invention is to provide an electricfuse device, having a fuse tube pivotally supported at one end forswinging movement, with a novel latching and fuse link extracting meanscarried by the tube and operative upon overload of the circuit toextract the fuse link from the tube and release the tube for swingingmovement to open-circuit position.

A further important object of the invention is to provide a simple andnovel snubbing or shock absorbing means for retarding swinging movementof the fuse tube to its open-circuit position.

An additional oba'ect resides in the provision of an improved pivotalmounting and novel arrangement on the tube of the fuse link extractingand latching elements interconnected by motion transmitting means which,in the closed-circuit conditionof the fuse link, interlocks saidelements against relative pivotal movement so that additional stress isnot applied to the fuse link by the latching impact.

It is a further object of the invention in one of its embodiments toprovide two relatively short tubes through which the fuse link isthreaded, each pivotally supported at one end on an insulated terminalwith a fuse link extracting and tube latching means mounted on thepivoted end of each tube, together with spring means for moving saidtubes to open-circuit position.

Other subordinate objects and advantages of the invention will morefully appear as the description proceeds in connection with theaccompanying drawings, wherein similar reference characters designatecorresponding part throughout the several views and appended claims:

Figure 1 is a side elevation illustrating a double tube type fuse deviceembodying the present invention wherein the fuse containing tubes arelatched in aligned closed-circuit position,"

Figure 2 is an enlarged fragmentary side elevation of the pivotallymounted end of one of the fuse tubes latched in its closed position;

Figure 3 is an enlarged detailed view showing the mitered weather guardson the free open ends of the tubes;

Figure 4 is a fragmentary side elevation of one of the tubes, similar toFigure 2, but showing the tube in open-circuit position;

Figures 5 and 6 are detail side elevations of the link extracting andlatch assembly of Figures 1 through 4 showing the latter in open andclosed position respectively;

Figure. 7 is an end elevation shown in Figure 6; v

' Figure 8 is a detail vertical sectional view showing the retarding orbraking mechanism for each tube with the latter disposed in its closedposition';

Figure 9 is a similar sectional view, the fuse tube being shown in itsopen position;

Figure 10 is a combined top plan and vertical sectional view showing themounting and arrangement of the spring means for moving the fuse tube toopen-circuit position; and

Figure 11 is a combined and elevation and top plan view of the lowerportion of Figure 10, the spring and mounting members being omitted inthe plan view portion thereof,- a

Referring in further detail to the drawings, and particularly to Figure1 thereof, a double fuse type arrangement made up of a pair ofhorizontally spaced insulators 2 rigidly mounted upon a suitable base 1is illustrated. Upon the upper end of each insulator a metal terminalmember 3 is securely fixed. The usual line conductors (not shown) areadapted to be connected to the respective members 3 in any suitablemanner. A pair of fuse tubes 44' are respectively supported upon theterminals 3 for swinging movement from a circuit-closing position inalignof the assembly ment with each other to an open-circuit posi-,

tion. A flexible link '7 is threaded through these tubes, which areconstructed of a suitable insulating material. Link 7 is provided withthe usual intermediate fusable section as is well known in the art.Means is associated with each of the tubes to releasably latch the tubesin closed-circuit position and to automatically ea:- tract the sectionsof the link 7 from the respective tubes upon overload Of the electricalcircuit. Since this latching and link attracting means for each tube, aswell as the means for swingingly mounting the respective tubes upon theterminal 3 is of the same construction, the detailed description of onewill suffice for both.

As shown most clearly in Figures 2 and 4 of the drawings, a casting 9 issuitably fixed at one of its ends to one end of the fuse tube and itsother end is pivotally supported by a pin 15 mounted adjacent itsopposite ends in upstanding bearing lugs or cars formed on terminalmember 3. Preferably, a spacing sleeve 23 surrounds shaft 15 and a pairof coil springs 14 surrounds said sleeve. These springs at one of theirends are secured to member 3 by suitable fastening elements 24 and attheir other ends engage casting 9 and exert a rotating'thrust to casting9. It will, therefore, be understood that these spr ngs. tend to biasthe BESt- AVAIIABEE%%- fusevtube; in oneairjeetio.v "-.-from.a.closedraircui't; position to uneven-circuit. position about normalto-the plane; of terminal 3.;

The fuse tube is releasably held-in-.the.closedcircuit position ofFigure l-by means of thelatch element 5 pivotally mountedintcrmediateitscnds as at 13 upon the casting 9. One endof latch 5. is provided witha latching nose for engagement with the upper end ofa complementarykeeper 6 pivotally mounted as at. 6. ago-on terminal and. biased tonormal position by a. suitable keeperspring. Theother end. of latchelement 5. pro vided with a longitudinally extending. slotfif, thepurpose of which will be presently explained...

Theforward. end of casting, 9 opposite pivot 13 supports a terminalbracket member havinaa link extracting. member 8 pivotally mounted.thereon as at 12. Extracting member, 8 .is providedat one end with aslot (Figure 7) through which the use link 7 is slidably received.Member 8 at its other endhas an angularly. projecting partcarrvi'ng a.pin 8 which is slidably engaged inthe, slot 5' of the latch element 5. Aspring 11 having one end coasting with member 8, surrounds pivot 1.2.and.

I has its other end protruding beyond pivot 12 in adi'rectioncppositethat of member 8.. into abut= ting engagement with. theterminalbraclcet, of casting 9. The ends of. link 7 extend through andfrom the slotted end of respective members 5 longitudinally over themembers 8 and around beyond pivots 1.2.. and aresecurely. jlmedto theterminal brackets of casting 9 by thumb screws 10. The. link 7., whendrawn tight between the respective thumb screws 10. tensions therespective springs 11 thus conditioning them to urge members 8 in onedirection around their pivots to maintain the fuse, link 7 un= dertension. In this normal operative positionof the parts, as seeninFigures. 1 and 6, with the fuse arms being swung to closed-circuitposition, latch element 5 and keeper 6- are cooperatively engaged andpin 8' isverticallyv aligned. with pivot 13 of latch element 5, andhorizontally offset-with respect to pivot 12 of member 8, which pivot issubstantially vertically aligned with thepivat axis of keeper 5 as shownmost clearly Figure 2.. Due to the abovedescribed location of pin 8- andthe various pivot points and as the keeper spring. is relatively: l ht,the only substantial forces act cut 5 and keeper 6 in this normaloperating position are applied lengthwise between pivot. 1.3 the pivotof keeper 6. As a conse-v quence, no effective rocking forces areapplied to. latch element 5, nor is additional stress placed upon fuseli'nh a result of the tension of fuse. tube actuating springs 14.

From the above description, it will be readily seen. that upon ruptureof the fusable. section of linlc 7 overload on the circuit the tensionalstress of springs If is releasedto rock members 8 around pivots 1.2 tothereby extract the di'scon nectedv end sections of the link from therespective tubes 4 and 4' and to simultaneously effect arcuate movementof pins 8' against the sides of slot 5 of latch elements 5 torespectively. roclc latch elements 5 about pivots 13. in a directiontodisengage noses of latch elements 5 from the keepers 5 of terminals 3.Springs. 14. then swing the fuse tubes upwardly about pivot pins 15 toopenmircuit position.

Preferably castings 9 carry baskets 22 having, perforated walls whichreceive the extracted end portions of the fuse links. The free ends ofthe tubes 4. and 4' are preferably provided with nonmetallic shields orcover elements, respectively in aieatea-ebunumerals zfliand .1L h zvvosedz'endsci Ofglll'hiQh areemiter attora sume .-..clo.selv.varllqlrelation with-,eaelno h n hazlosedscitcuitvq. tionof the tubes; as;seenin'EiQl 'IQS and. 3; and;v

- thus provide a; semi-weatherproof condition. l

the oven ends of-thedubes;

As -the ener y, storediin the springs 14 is-;con siderable, the presentinvention pizovidesa simple andeffeetive means for-controlling or' ovi rill s he. action. f he.- svrinos; o. minimize-shock nd vossibleldama fltqaitirts of; the tub mounting, assembly inthemovemenvofthetube toits-ovencjircuit, position. Referrin more vartieul rlv; toli'iauresqfiand. 9 ofthedrawings, a. braking member in the form. ofahousing 16 is-pivo-tally sup-.

eocentrically with-relation to thepin- 1,5 and aside;

wall opposed to casting 9- havingan opening therein, through which a lug9 on casting- 9 egrtends, Lug 9' has frictional contact with theoccentrically curved inner wall surface of the housing. in the upwardpivotal movement of casting 9 aboutpin 15, whereby the brahehousing16-.will be swung upwardly in an are about pivot: 17. At itslower endopposite pivot 17 housing 16 has.;a pro-. r'eeting' apertured flangethrough which a bolt-19' loosely extends. Bolt-19, at its; lower end isnon= rotatably connected. with the baseof terminal A coil spring 18andspring cover 20 are assembled on bolt 19 by a. nut threaded on theupper end; ofthebolt bearing upon cover ZOIto. adjust or; regu= late,the resistance of-spring 18 to pivotal rocking, movementof. brakehousinglfi From the above-description, it will be appar-q cut that whenthe fuse tube and castings 9 are swung nnwardly about pin15, by theaction of M, such movement of the tube and cast in to the finalopen-circuit position is promos-- sively retarded or restrainedby thefrictional en-. gagcment of lug 9' with the. eccentrically curvedhousing wall 16, the upward rocking movementof housing 9 effecting.acompression of spring 18' which applies a progressively. increasingresist-. ance to the movement of the housing relative to the terminal 3,as, most clearly seen in Figure 9 ofthe drawings. In this manner,violentshoch orimpact is avoided and possible breakage or damageof thecontacting'parts of the assembly is ob-. viated.

The various parts of the improved electrical fasedevice illustrated areof simple and durable: structural form and can be readily fabricatedfrom materials commonly used theart for this nurpose. It will alsolie-apparent that the devicecan be made in various different sizes forlow or high voltage circuits and is adaptable to single tube fusesv Theinvention may be embodied in other specific forms without departing fromthe spirit or essential characteristics thereof. The present embodimentsare therefore. to be considered in all respects as illustrative and notrestrictive, the scope of the invention being indicated by the up pendedclaims rather than by the foregoing de-. scription, and all changeswhich come within the meaning and range of equivalency of the claims aretherefore intended to be embraced therein.

Having described our invention, we claim:

[1. In an electric fuse of the character described comprising; a mainsupporting base I, two insulators 2 mounted. and spaced apart upon saidbase I, a. separate mechanism supporting base 3 mounted upon each of thesaid insulators, two duplicate tube assemblies mounted one on each ofthe bases on the insulators, each assembly consisting of a fusecontaining tube 4 with one end thereof attached in a housing 9 that isswingable on a shaft I5 supported in a second housing It that isswingable on a shaft l1 supported on a base 3; a latch arm 5 mounted ona shaft l3 supported on the housing 9, said arm 5 having an L-shapedend, a latch member 6 supported on the base 3, a coil spring attached tosaid latch member and positioned normally disposed to urge the free endof the latch away from the housing IS, the L-shaped end of the arm 5being adapted to make contact with the latch 6 when the tube 4 ispositioned parallel to the base I; a fuse inserted through said tubes,each end of the fuse attached by thumb screws ID to part of the housing8, said fuse in taut condition being adapted by trigger means on the endof arm 5 to retain said tubes in parallel position with relation to baseI, and. being adapted to allow the free ends of the tubes to move awayfrom the center portion of the base I as a result of rupture of thefuse; spring means mounted in each said housing It and being adapted tourge the free ends of said tubes away from the center portion of base Iwhen said fuse is in ruptured condi tion.]

[2. In an electric fuse of the class described comprising; a mainsupporting base I, two insulators 2 mounted and spaced apart upon saidbase I, a separate mechanism base 3 mounted upon each of saidinsulators, attached to each mechanism base a swingable latch assemblyconsist ing of a metal housing 9, a latch arm 5 mounted on a shaft l3through the housing swingable por tion, an ejector 8, a coil spring llmounted on a shaft 12 and positioned normally to urge the ejector 8 awayfrom the latch arm 5; an L-shaped extension integral with the latch arm5, a stud 8' integral with the ejector 8, said stud 8' positionedslidable in a slot 5 in the latch arm 5; the housing having a round holetherein, a tube 4 attached by one end thereof in said round hole, anelectric fuse l threaded through said tube 4 and over the ejector 8 andattached to the swingable housing 9 by a thumb screw It]; said fuse alsothreaded through a similar tube attached to the other companion similarlatch assembly, said fuse positioned in taut condition being adapted tohold said tubes in parallel position with relation to the plane of thebase I, a latch hook member 6 mounted on each mechanism base andpositioned to engage the L-shaped extension of each latch arm 5 when thefuse is in threaded tautcondition; springs l4 mounted on a shaft l5 ineach mechanism fixed portion, the swingable portions of the housingsmounted on said shafts, the springs in the housing fixed portionsnormally set to urge the swingable portions of the assemblies to aposition away from the center portion of the base I; said two tubesbeing approximately equal in length, the free end of each tube beingmitered and adapted to coact and fit adjacent each other when thethreaded fuse is in taut condition and adapted to separate and swingapart upon rupture of the said fuse threaded through the two tubes] '3.In an electric fuse device, spaced insulated terminals; a fuse tube;means pivotally mounting said tube at one nd thereof upon one of saidterminals, a fuse link extending through said tube; means normallyelectrically connecting said link with said terminals; a fuse linkextracting- Zeverpivotally mounted on said tube and having means at oneend engaged with said fuse link; spring means biasing said lever in adirection to maintain said link under tension; means releasably holdingsaid tube against movement to opencircuit position including a latchelement pivotally mounted on said tube; and a motion transmittingconnection between said link extracting lever and said latch elementadapted upon fusing of the link to release said lever for movement insaid one direction to extract the link from the tube and release saidlatch element to simultaneously release the tube for pivotal movement toopen-cirouit position.

4. An electric fuse device as defined in claim 3, wherein said motiontransmitting connection comprises a direct pin and slot connectionbetween said link extracting lever and latch element.

5. An electric fuse device as defined in claim 3, wherein said linkengaging means at said one end of said extracting lever comprises a slotin said extracting lever and said link extends through said slot andlongitudinally over said lever to said terminal connecting means.

6. An electric fuse device as defined in claim 3. wherein said motiontransmitting connection comprises a pin on said extracting lever spacedfrom the pivot thereof and disposed in closed circuit condition of saidtube and fuse link in engagement with said latch element at the point ofintersection of a plane containing the pivot axis of said lever anddisposed substantially normal to the longitudinal axis of said latchelement to lock said latch element against movement to non- Zatchingposition.

7. An electric fuse device as defined in claim 3, together with meansrestraining movement of said tube to open-circuit position.

8. An electric fuse device as defined in claim 7, wherein saidrestraining means comprises a member pivotally mounted on said oneterminal and having a cam surface eccentric to the pivot of said tube, alug movable with the tube about said pivot and friotionally coactingwith said cam surface to pivotally move said member, and spring meansyieldingly resisting said pivotal movement of said member relative tosaid tube.

9. An electric fuse device as defined in claim 3, together with anenergy storing device operatively associated with the pivoted end ofsaid tube and energized by movement of the tube to closedcireuitposition to pivotally move said tube to open-circuit position uponrelease of the tube by said latch element.

10. An electric fuse device as defined in claim 9, together with meansgoverning the effective action of said energy storing device to brakemovement of said tube to open-circuit position.

11. An electric fuse device as defined in claim 3, wherein said pivotalmounting for said tube comprises a casting fixed to the tube and mountedfor swinging movement about a pivot supported on said one terminal, andspring means coacting with said casting and operative upon releaseoftilze tube to swing said tube to open-circuit posit n.

12.'An electric fuse device as defined in claim 11, together with meansfor progressively retarding movement of said tube under the action ofsaid spring means.

13. In an electric fuse device, comprising a ter minal, a fuse tube, andmeans pivotally mounting said tube at one end thereof upon saidterminal: a fuse link extending through said tube;

BEST is,

means normally electrically connecting said link with said terminal; afuse link extracting member movably mounted on the pivotallg supportedend of said tube and engaged with said fuse link in spaced relation fromsaid terminal connecting means; spring means biasing said member in adirection to maintain said fuse link under tension; means releasablyholding said tube against movement to open-circuit position including alatch element movably mounted on said pivotallg supported end of thetube; and a motion transmitting connection between said extractingmember and said latch element, whereby upon fusing of the link saidmember is moved in said biased direction to extract the link from thetube and to simultaneously actuate said latch element to release thetube for movement to open-circuit position.

14. In an electric fuse device, spaced terminals; a pair of fuse tubes;means pivotally mounting said tubes on the respective terminals formovement into and out of axially aligned relation with each other; aflexible link extending through said tubes and having an intermediatefusible section; means normally electrically connecting said link atopposite ends thereof with the respective ter-. minals; fuse linkextracting means movably mounted on each tube adjacent to its pivotedend and maintaining the fuse link under tension in the alignedclosed-circuit position of said tubes;

latch means individual to said tubes to releasablg retain the tubes inaligned closed-circuit posi- LABLE CO 10 tion; and a motion transmittingconnection between each link extracting means and the corre-' spondingtube latch means operative upon fusing of said fusible link section, toactuate the respective latch means and release said tubes for movementto open-circuit position.

15. An electric fuse device as defined in claim 14, together with meansfor applying a progressively increasing retarding force to movement ofsaid tubes to open-circuit position.

16. An electric fuse device as defined in claim 14, together with anenergy storing device operativelg associated with each tube andenergized by movement of said tubes to aligned closed-circuit positionto pivotallg move said tubes, upon release of the tubes by therespective latch means, to open-circuit position.

17. An electric fuse device as defined in claim 16, together with meansgoverning the effective action of each energy storing device to restrainmovement of said tubes to open-circuit position.

FITZH-UGH HOBSON TURNHAM. EDGAR. WILLIAM GARRZSON, J R.

REFERENCES CITED- Ihe following references are of record in the file ofthis patent or in original patent:

UNITED STATES PATENTS Number Name Date 675,383 Greenstreet et a1. June4, 1901 2,365,113 Schultz Dec. 12, 1944

